1. Field of the Invention
The present invention relates to an image sensing technique.
2. Description of the Related Art
In a digital camera, conventionally, an object image is formed on an image sensing element through an imaging lens, and image information obtained by the image sensing element is displayed on an LCD (Liquid Crystal Display). The digital camera includes an electronic viewfinder (EVF) to observe the image information formed on the LCD (Japanese Patent Laid-Open No. 5-134294).
Also known is a digital camera using live view display in which a shutter arranged on the whole surface of an image sensing element is opened to project an object image on the image sensing element, thereby displaying the video in an image display LCD (Japanese Patent Laid-Open No. 2001-186401).
International Patent Publication No. 06/039486 and Ren. Ng, et al “Light Field Photography with a Hand-Held Plenoptic Camera”, Stanford Tech Report CTSR 2005-02 propose an image sensing apparatus using a method called “Light Field Photography”. This image sensing apparatus includes an imaging lens, a microlens array, an image sensing element, and an image processing unit. Sensed image data obtained from the image sensing element includes not only the light intensity distribution on the light-receiving surface but also the information of the light traveling direction. The image processing unit can reconstruct an image observed from a plurality of viewpoints or directions.
However, when the image sensing apparatus including the microlens array arranged in front of the image sensing element senses an object as shown in FIG. 20A using an aperture stop having a circular opening portion, the live view display image includes a non-light-receiving area, as shown in FIG. 20B. For this reason, it is difficult for the user to determine the focus position.